Researcher pioneers variable-rate fumigation

Sean Ellis/Capital Press
Nematologist Harry Kreeft looks at the results of soil tests for nematodes on 2-acre grids at the Western Laboratories facility in Parma, Idaho, Jan. 24. The area in the green is clear of nematodes and doesn't need fumigation, the yellow area needs mild fumigation and the red area needs heavier fumigation.

A nematologist and plant pathologist based in Parma, Idaho, is a leader in the use of variable-rate fumigation to control nematodes. Instead of fumigating entire fields, this approach involves testing soil in 1- or 2-acre grids and then applying fumigants only where they're needed.

PARMA, Idaho — A researcher based in southwestern Idaho is pioneering the concept of variable-rate fumigation to control nematodes in multiple crops.

Unlike conventional techniques, in which entire fields are uniformly fumigated, variable-rate fumigation involves testing soil in 1- or 2-acre grids and then applying fumigants only where they’re needed.

“That allows the grower to take out the hot spots and not overuse fumigants in a particular field,” says Harry Kreeft, a nematologist and plant pathologist with Western Laboratories. “It just doesn’t make sense to put a treatment on an area where you don’t have a problem.”

The concept involves treating each grid as an individual field, he says.

Several soil samples are taken within each grid and an analysis produces a map of nematode hot spots.

He likens the concept to removing a wart on your thumb.

“You don’t get chemotherapy; you just remove the wart,” he says. “That’s how you can look at variable-rate fumigation. You take out the hot spots, the cancers, in the field. You don’t nuke the whole field.”

Kreeft, 50, was born and educated in the Netherlands and moved to the United States in 1996 to attend the University of Idaho for two years. He went to work for Western Laboratories in 1998 and shortly after began pioneering the idea of applying fumigants in varying rates.

Kreeft says variable-rate fumigation is a growing trend and one of the driving factors is a shortage of Telone II, a soil fumigant used to control all major species of nematodes in vegetable, field and nursery crops, fruit and nut trees and grapes.

“There’s just not enough to go around, so growers are looking for alternatives and the variable-rate idea just fits perfectly,” he said.

Kreeft says the approach reduces fumigation by about 40 percent and as much as 75 percent in some fields. Fumigation costs about $340 an acre.

“If you can save $340 an acre on 75 percent of your field, that’s a lot of money,” he says. “That’s a new pickup.”

Western Laboratories owner John Taberna, who hired Kreeft, said beneficial microorganisms are not as severely set back when variable-rate fumigation is used.

“Their recovery rate is much faster with variable-rate than it is with a one-size-fits-all approach,” he said.

Taberna said many farmers are still reluctant to try the variable-rate approach despite the cost savings.

“The farmers are so scared of sticking their neck out because they’re so used to treating everything and the crop advisors are afraid to advise the farmers to do it, too, because their neck is stuck out also,” he said.